Association of HLA-DR4 (DRB1*0404) with human papillomavirus infection in patients with focal epithelial hyperplasia

OBJECTIVES

To determine gene frequencies of HLA-DR alleles in 22 Mexican patients with focal epithelial hyperplasia and compare them with those present in ethnically matched healthy subjects, as well as to determine the types of human papillomavirus present in the lesions.

DESIGN

Prospective and retrospective observational study.

SETTING

Dermatology outpatient clinic in a general hospital.

PATIENTS

Twenty-two patients with clinically and histologically confirmed focal epithelial hyperplasia seen within a 10-year period.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Results of high-resolution DNA typing for HLA-DR alleles and biopsy for viral typing.

RESULTS

HLA-DR4 (DRB1*0404) was significantly increased (P<.001; odds ratio, 3.9; 95% confidence interval, 1.86-8.03). Seventeen (85%) of 20 patients had human papillomavirus subtype 13. The data on human papillomavirus differed from reports elsewhere that described association with human papillomavirus type 32.

CONCLUSIONS

The HLA-DRB1*0404 allele suggests that Amerindian populations are at risk, and in this group, the Mexican population studied was affected only by human papillomavirus type 13.

[Association of the HLA-DQB*0501, allele of the major histocompatibility complex with gastric cancer in Mexico]

Etiology of gastric cancer is related to environmental and host factors, Helicobacter pylori infection is the main environmental factor, but it has been also proposed that some major histocomnpatibility complex genes are related to susceptibility and resistance to develop Helicobacter pylori associated gastric diseases. The aim of this study was to study distribution and frequency of some HLA -DQ genes, among Mexican patients harboring gastric diseases. We studied 20 subjects suffering from gastric cancer and 40 subjects harboring Helicobacter pylori-associated chronic gastritis. Diagnosis was confirmed by biopsy. HLA genotyping was performed by a polymerase chain reaction procedure. Ninety nine healthy individuals were also utilized for comparative purposes. Patients with gastric cancer displayed high frequency of HLA-DQA1*0601 (p = 0.003; OR = 20.9, 95% CI = 2.11-506.2) and HLA-DQB1*0501 alleles, the latter when compared to patients with chronic gastritis (p = 0.04; OR = 3.58, 95% CI = 1.05-12.5) and to healthy individuals (p = 0.002; OR = 4.5, 95% CI =1.59-12.7). According to our results, in addition to Helicobacter pylori infection, there are immunogeneic markers of the HLA-DQ region, which are determinant in confering susceptibility for gastric cancer.

HLA-DRB1 alleles encoding the “shared epitope” are associated with susceptibility to developing rheumatoid arthritis whereas HLA-DRB1 alleles encoding an aspartic acid at position 70 of the β-chain are protective in Mexican mestizos

The risk to develop rheumatoid arthritis (RA) has been associated with the presence of HLA-DRB1 alleles encoding the "shared epitope" (SE). Additionally, HLA-DRB1 alleles encoding an aspartic acid at position 70 (D70+ ) have been associated with protection against the development of RA. In this study we tested the association between either SE or D70+ and rheumatoid arthritis in Mexican Mestizos. We included 84 unrelated Mexican Mestizos patients with RA and 99 unrelated healthy controls. The HLA-typing was performed by PCR-SSO and PCR-SSP. We used the chi-squared test to detect differences in proportions of individuals carrying at least one SE or D70+ between patients and controls. We found that the proportion of individuals carrying at least one HLA-DRB1 allele encoding the SE was significantly increased in RA cases as compared to controls (p(c) = 0.0004, OR = 4.1, 95% CI = 2.2-7.7). The most frequently occurring allele was HLA-DRB1*0404 (0.161 vs 0.045). Moreover, we observed a significantly increased proportion of HLA-DRB1 SE+ cases with RF titers above the median (p = 0.005). Conversely, the proportion of individuals carrying at least one HLA-DRB1 allele encoding the D70+ was significantly decreased (p(c) = 0.004, OR = 0.4, 95% CI 0.2-0.7) among RA patients compared with controls. In conclusion, the SE is associated with RA in Mexican Mestizos as well as with the highest titers of RF.

HLA class II genotypes in Mexican Mestizo patients with myasthenia gravis

Myasthenia gravis is an autoimmune, heterogeneous disorder, characterized by the presence of antibodies against acetylcholine receptors at the neuromuscular junction. There is a strong evidence that an individual's genetic composition is an important predisposing factor for the development of the disease. To correlate HLA class II genotypes with thymic pathology in Mexican Mestizo patients who had been subjected to thymectomy. HLA class II genes were analyzed in 60 patients and in 99 healthy ethnically matched controls. Thymic hyperplasia, atrophy, thymoma, and normal histology were encountered in 56, 33, 8 and 2% of patients, respectively. HLA-DR11 was significantly increased in patients with thymoma compared with healthy controls (pC = 0.001, OR = 13.35, 95% CI 3.5-51.3), compared with the subgroup of hyperplasia patients (pC = 0.005, OR = 15.5, 95% CI 2.78-95.58) and with the atrophy subgroup (pC = 0.04, OR = 10.5, 95% CI 1.75-70.95). This study provides the evidence of an association between HLA class II alleles with clinical and genetic heterogeneity in myasthenia gravis, particularly in those with thymoma (HLA-DR11).

[Predictors of colectomy in patients with ulcerative colitis. A cohort analysis of 184 cases]

BACKGROUND

At the present time procto-colectomy is the only potentially curative therapeutic measure for patients with ulcerative colitis (UC). Due to its morbidity and mortality, several prognostic indexes have been proposed to identify subjects in whom surgery could be beneficial. However, they have limited availability or they are very cumbersome for the individual patient.

AIM

To analyze demographic, clinical and biochemical variables in a group of 184 Mexican patients with UC in order to identify predicting factors for procto-colectomy.

PATIENTS AND METHODS

Subjects were divided into two groups: A. Those in whom a procto-colectomy was performed (n = 52) and B. Patients on medical treatment in = 132). Continuous variables were analyzed by means of the Student's t test and categorical variables by means of chi-square statistic. A multivariate analysis was performed using logistic regression.

RESULTS

The main indication for surgery was failure to medical treatment (78%). Procto-colectomy was elective in 28 cases and an emergency procedure in 14 (7 failures to medical treatment, 4 colonic perforations, 2 toxic megacolons and 1 uncontrolled hemorrhage). All operated subjects had pancolitis and showed more bloody bowel movements per day (> 10), fever (> 38.5 degrees C), tachycardia, hipoalbuminemia and hospitalizations. Only hypoalbuminemia in subjects with universal colitis was consistently associated to procto-colectomy.

CONCLUSION

Pancolitis, hypoalbuminemia and previous hospitalizations were the strongest predictors of procto-colectomy in our cohort. Thus, serum protein determinations can be useful in patients with universal UC to decide surgical therapy.

[Immunogenetics of chronic ulcerative colitis]

Genetic factors have a definitive role in the etiology of ulcerative colitis (UC). The mode of inheritance suggests a polygenic disease with the penetrance of the genetic factors being strongly influenced by environmental factors. Several studies have been reported associations between UC and the polymorphism of genes that are located in the major histocompatibility complex (MHC) on the short arm of chromosome 6. The human leukocyte antigen (HLA) class II genes are candidates for a role in the pathogenesis of UC, because their products play a central role in the immune response. The MHC region contains numerous immune related genes, and it has now become clear that different alleles of the MHC genes are strongly linked. Association studies have suggested a role for HLA-DR alleles in disease susceptibility to UC. Thus, HLA-DRB1*0103, DRB1*1502 and DRB1*12 were found to be positively associated with UC. On the other hand, the tumor necrosis factor alpha (TNF-alpha) gene encodes a proinflammatory cytokine that is found in increased concentrations in the mucosa of patients with inflammatory bowel disease. The regulation of TNF expression is in part genetically determined because the polymorphisms -238, -308, -863, -857, and -1031 found in the promoter region are associated with increased TNF production. Recent data suggests that TNF polymorphism may be more important in determining susceptibility to UC and these TNF markers could predict response to infusion with chimeric anti-TNF antibody.

Clinical and genetic heterogeneity in Mexican patients with ulcerative colitis

Ulcerative colitis (UC) is an inflammatory bowel disease of unknown etiology. Genetic factors implied on its onset and severity may include genes located within the class II major histocompatibility complex (MHC) region. The aim of this study was to determine the relationship between human leukocyte antigen (HLA)-DRB1 alleles with the clinical disease patterns of UC in Mexican Mestizo patients. High-resolution HLA typing was performed by polymerase chain reaction-sequence specific oligonucleotide (PCR)-SSO reverse dot blot and PCR-single-strand polymorphism in 67 patients with UC and 99 ethnically matched healthy controls. UC patients overall showed an increased frequency of HLA-DR1 as compared with healthy controls (17.1% versus 5%, [pC = 0.003, OR = 3.9]). Patients with extensive colitis showed increased frequencies of HLA-DR1 (pC = 1 x 10(-10), OR = 13.9), HLA-DRB1*0103 (pC = 1 x 10(-3), OR = 21.7), HLA-DRB1*0102 (pC = 0.007, OR = undetermined), and HLA-DR15 (pC = 1 x 10(-3), OR = 8.5) when compared with healthy controls. We also found a statistically increased frequency of HLA-DR15 in UC patients with extensive colitis compared with UC patients with only distal colitis (18.7% versus 1.8%, pC = 0.03; OR = 12.2). When patients who underwent proctocolectomy were compared with those who did not, an increased frequency of HLA-DRB1*0103 was observed (21.8% versus 4.9%; pC = 0.03; OR = 5.4; 95% confidence interval, 1.39-21.93). Also, patients with proctocolectomy showed increased frequencies of HLA-DR1 (pC = 1 x 10(-3), OR = 24.2) and HLA-DRB1*0103 (pC = 1 x 10(-3), OR = 50.6) when compared with healthy controls. We concluded that HLA-DR1 is associated with genetic susceptibility to UC in the Mexican Mestizo population. HLA-DR15 distinguishes a subgroup of patients with extensive colitis and the HLA-DRB1*0103 allele distinguishes a subgroup of severe form of disease that might require surgical management.

HLA study on two Mexican Mestizo families with autoimmune thyroid disease

Several studies have been done regarding the genetic susceptibility to autoimmune thyroid disease, particularly those related to the role of Major Histocompatibility Complex (MHC) genes in the etiology of the disease. In the present study, we report class I and class II MHC haplotypes in nine individuals affected by Hashimoto thyroiditis and Graves' disease who belong to two distinct Mexican families. In one of the families, Hashimoto thyroiditis was associated with the Human Leukocyte Antigen (HLA) HLA-DR3 allele whereas in the other family the disease was associated with homozygosity for the HLA-DR4 (DRB1*0407), HLA-DQ3 (DQB1*0302) haplotype. On the other hand, Graves' disease was found to be associated in one of the families with HLA-DR2 (DRB1*1501) and in the other with homozygosity for the HLA-DR7 (DRB*0701) and HLA-DQ2 (DQB1*0201) haplotype. These results confirm that in Mexicans as in other ethnic groups, genes located within the MHC region are related to the genetic susceptibility to develop autoimmune thyroid disease.

Tumor necrosis factor-alpha promoter polymorphisms in Mexican patients with systemic lupus erythematosus (SLE)

The major histocompatibility (MHC) genes including TNF-alpha, HSP70 and HLA genes have been associated with systemic lupus erythematosus (SLE) in several populations. In this study we analyze the polymorphism of TNF-alpha promoter in 51 Mexican Mestizo SLE patients and 55 ethnically-matched healthy controls by polymerase chain reaction methods. No statistically significant differences were observed in the TNF -308 allele and genotype distribution between patients and healthy controls. However, we found a significant increase in the TNF G/A -238 genotype and in the TNFA -238 allele frequencies in the SLE group when compared with healthy controls (Pc = 0.03, OR = 4.77 and Pc = 0.02, OR = 3.62, respectively). DRB1 analysis showed a similar distribution in patients and controls. Linkage disequilibrium was observed for five haplotypes: DRB1*1401-TNFA-238 (D = 0.84; D' = 1.0; P = 0.015); DRB1*0301-TNFA-238 (D = 1.38; D' = 0.41; P = 0.042); DRB1*1106-TNF2-308 (D = 0.9; D' = 1.0; P = 0.0006); DRB1*1104-TNF2-308 (D = 0.83; D' = 0.45; P = 0.02) and DRB1*1406-TNF2-308 (D = 0.83; D' = 0.45; P = 0.02). Our data suggest that the association between the TNF-alpha -238 polymorphism and SLE could play a major role in disease susceptibility.

Haplotype distribution of class II MHC genes in Mexican patients with systemic lupus erythematosus

The objective of this project was to determine the association of the DQA1*0501 allele in the susceptibility to develop systemic lupus erythematosus (SLE) in Mexicans. Frequencies of generic MHC Class II genes (HLA-DR, DQA and DQB1) were determined by DNA typing in 58 Mexican mestizo SLE patients and 96 ethnically matched controls. Statistical analysis was performed by chi-square and Fisher's exact tests. The DQA1*0501 allele was found to be in linkage disequillibrium with H LA-DR3, DR11, and DR14. This explains the lack of association with the allele alone, and the evident strong association of SLE with the [HLA-DR3-DQA1*0501-DQB1*0201] and [HLA-DR1-DQA1*0101-DQB1*0501] haplotypes. It was also found a significant decrease (protection) of the [HLA-DR8-DQA1*0401-DQB1*0402] haplotype which is known to be a characteristic haplotype among the indigenous population of Mexico. These data shows that the susceptibility to SLE in Mexicans is more strongly influenced by the MHC haplotypes than by single alleles. The suggestion that these genes do not act alone but in combination, makes the identification of haplotypes mandatory.

Immunologic, genetic and social human risk factors associated to histoplasmosis: studies in the State of Guerrero, Mexico

Immunologic and occupational aspects of the susceptible population exposed to Histoplasma capsulatum, the causative agent of histoplasmosis were analyzed in the Mexican State of Guerrero. Three areas were studied, Juxtlahuaca, Olinala, and Coyuca; in the first two, their populations refer contact with bat guano and/or avian excreta, which contain nutrients for fungal growth, while the Coyuca population referred no contact with the above mentioned excreta. Previous infection with H. capsulatum was determined by histoplasmin-skin test, and the response was higher in men than in women (93.87, 85.71, and 6.6% for men, and 78.94, 66.6, and 0% for women) in Juxtlahuaca, Olinala, and Coyuca, respectively. Labor activities related to a persistent contact with the fungus were considered as an occupational risk factor, histoplasmin-skin test reached 88.57 and 36.36% of positive response in individuals with high and low risk activities. A high percentage of histoplasmin responses was observed in subjects with constant contact with H. capsulatum, such as, cave-tourist guides, peasants, and game-cock handlers, and generally they developed the largest diameter of skin reactions. Genetic risk factor was determined by studying the gene frequency of the Major Histocompatibility Complex antigens in a sample of individuals and their degree relatives in Juxtlahuaca, Olinala, and Coyuca. Significant differences were found for HLA-B22 and B17 antigens in Juxtlahuaca, and for HLA-B22 in Olinala, in comparison to the usual gene frequency observed in the normal Mexican population. HLA results were important, considering that HLA-B22 was previously found to be possibly related to pulmonary histoplasmosis in Guerrero.

HLA-DR7 in association with chlorpromazine-induced lupus anticoagulant (LA)

The presence of anti-phospholipid antibodies (aPL) has been associated with the major histocompatibility complex (MHC) genes. These autoantibodies occur in individuals with infections such as that produced by the human immunodeficiency virus 1 (HIV-1) or with syphilis, but they can also occur in drug-induced lupus-like syndromes. In the present study, we analysed the presence of aPL (detected as lupus anti-coagulant) and its relationship with the MHC markers in 93 Caucasian psychiatric patients chronically treated with chlorpromazine. Forty-one out of 93 patients were positive for LA, and the HLA-DR7 antigen was significantly increased in LA-positive patients as compared to normal controls or LA-negative patients (PC = 0.024, RR = 2.12 and P = 0.05, RR = 1.57, respectively). Likewise, we noted a significantly increased frequency of HLA-B44 in LA-positive patients as compared to normal controls (PC = 0.024, RR = 2.12), but not when compared to aPL-negative patients. No significant differences were found among any other class I, II or III MHC antigens. Haplotype analysis showed that DR7 was mostly part of the HLA-B44-DR7-FC31 and B7-DR7-SC31 haplotypes. These results suggest that the HLA-DR7 antigen might be playing a role in the production of aPL in chlorpromazine-treated patients.

Further evidence of the role of HLA-DR4 in the genetic susceptibility to actinic prurigo

BACKGROUND

Actinic prurigo (AP) is triggered by sun exposure. Its prevalence in Mexicans seems to be particularly high, which suggests a genetic susceptibility.

OBJECTIVE

Our purpose was to determine the role of major histocompatibility complex (MHC) genes in the genetic susceptibility to AP.

METHODS

Fifty-six Mexican Mestizo patients with AP underwent serologic typing for HLA class I and class II antigens. Class II MHC genes were also studied by DNA analysis. Findings in patients were compared with 100 ethnically matched healthy controls.

RESULTS

We found that 92.8% of patients with AP were HLA-DR4 positive (corrected p = 0.002; odds ratio [OR] = 10.1). The class I antigens HLA-A28 and HLA-B39 (B16) were also significantly increased (p < or = 0.000001, OR = 20.9 and p = 0.0001, OR = 6.7, respectively) compared with normal controls. Allele-specific oligonucleotide DR4 subtyping showed that 80.7% of HLA-DR4+ patients with AP were also positive for the DRB1*0407 allele.

CONCLUSION

These results confirm the role of HLA-DR4 (DRB1*0407) in the genetic susceptibility to AP and raise the possibility of a role for class I MHC antigens HLA-A28 and B16 in Mexican patients.

[Immunogenetic study in Mexican couples with recurrent spontaneous abortions]

AIM

To study the HLA markers in Mexican couples who have suffered three or more spontaneous abortions.

DESIGN

The study included 24 couples with recurrent abortions and 32 with normal fertility.

METHOD

HLA class I (A, B, C) and class II (DR, DQ) typing was done with a standard microlymphocytoxity test. The intergroup differences were evaluated by chi-square and the Fisher exact test.

RESULTS

The frequency of the MHC markers in the males and females of couples with abortions were not significantly different from those in fertile couples. However, the abortion couples shared class I antigens more often than expected from random mating as compared to fertile couples, specially in the HLA-B locus. We also found a significantly decreased frequency of the HLA-B7 antigen in males belonging to the abortion group.

CONCLUSION

These results suggest that HLA-B antigens may be markers for genes related to pregnancy outcome in Mexicans.

Major histocompatibility complex genes in a Mexican family with deficiency of the second component of the complement system

Hereditary deficiency of the second component of the complement system is an uncommon condition that has been reported so far mostly in Caucasians. We describe a Mexican patient with undetectable C2 levels and absence of complement hemolytic activity. Major histocompatibility complex (MHC) genes in his family showed that the proband had the MHC haplotypes HLA-A25, B18, DR2, DQ1, SQ042/HLA-A24, B18, DR2, DQ1, SQ042. A strong genetic linkage of the deficiency of the second component of the complement gene and the HLA antigens A25, B18, and DR2, is well established in Caucasian populations. This suggests that the probable origin of the deficiency in our patient was admixture with Caucasian ancestors.

HLA-DR6 (possibly DRB1*1301) is associated with susceptibility to Takayasu arteritis in Mexicans

Takayasu arteritis is characterized by a "pulseless" condition and occurs frequently in young females from Asian and South American countries. This disease has been found to be linked with major histocompatibility complex (MHC) antigens in Japanese individuals. In the present study we compared gene frequencies of class I, class II, and class III MHC genotypes in patients with Takayasu arteritis and ethnically matched healthy controls. Serological typing was confirmed by molecular typing at the DNA level. We found significant increases in the frequencies of human leucocyte antigen (HLA)-DR6 and HLA-B62 in patients compared to the healthy controls (P corrected [C] = 0.0007, relative risk [RR] = 5.08; PC = 0.05, RR = 3.13 respectively). However, since the number of patients was considerably lower than the number of controls this can be considered as a tendency and not a true association. On the other hand, we found a significantly decreased frequency of HLA-DR4 in patients compared to healthy controls (PC = 0.04, RR = 0.34). At the DNA level, all DR6-positive individuals were HLA-DRB1*1301 whereas controls were HLA-DRB1*1301 (4.2%). Takayasu arteritis in Mexicans is probably associated with the HLA-DR6 (DRB1*1301) gene.